TECHNICAL FIELD
Generally, the invention relates to wave rotors. Particularly, the invention relates to a method and apparatus which reduces the temperature in through-flow and reverse-flow wave rotors and which reduces the temperature of a gas outflow driven by the wave rotors. Specifically, the invention relates to a method and apparatus which diverts a portion of cool air exiting the wave rotor as reinjection air and injects the reinjection air back into the wave rotor to evacuate residual hot gas from the wave rotor.